Valve arrangement and switching valve for regulating a mass flow

ABSTRACT

A valve arrangement for a switching valve and to a switching valve for regulating a mass flow in a refrigerating circuit or a heating circuit, comprising a valve housing, which comprises a feed opening and a discharge opening, comprising a valve piston, which comprises a valve-closing member, which buts against a through-hole between the feed opening and the discharge opening in a closed position on a valve seat and closes the through-hole, wherein the valve seat comprises a stop surface and a sealing surface which are oriented so as to be adjacent to one another, the valve-closing member comprises a supporting surface and a gasket surface which are oriented so as to be adjacent to one another, an elastic sealing element is provided on the valve seat or the valve-closing member, on which sealing element the sealing surface or gasket surface is formed, a sealing projection is provided on the sealing surface or the gasket surface and is oriented towards the opposite gasket surface or sealing surface, the supporting surface of the valve-closing member and the stop surface of the valve seat but against one another in the closed position and form a travel limitation between the valve-closing member and the valve seat, and the sealing projection is at least partially pressed into the sealing element.

This application is a continuation-in-part of U.S. application Ser. No.17/180,066 filed Feb. 19, 2021, which claims priority of GermanApplication No. 10 2020 108 762.4 filed Mar. 30, 2020. This applicationalso claims priority of German Application No. DE 10 2021 107 997.7filed Mar. 30, 2021. The disclosure of each of the foregoingapplications is hereby incorporated herein by reference.

The invention relates to a valve arrangement and to a switching valvecomprising a valve arrangement of this kind for regulating a mass flowin a refrigerating circuit or a heating circuit.

DE 10 2013 107 060 A1 discloses a switching valve for regulating a massflow in a refrigerating circuit or a heating circuit. This switchingvalve comprises a valve housing, which comprises a feed opening and adischarge opening. A valve-closing member is provided on a valve piston,which member in a closed position buts against a valve seat arrangedbetween the feed opening and the discharge opening. A pilot valve isprovided opposite the valve-closing member, which pilot valve comprisesa pilot hole in the valve seat, which opens into the through-hole andpasses through the valve piston. For actuating the valve piston, atravel-generating device is provided, which has an actuatable tappet,which receives a closing body that closes the pilot hole and can betransferred into an open position that unblocks the pilot hole with theclosing body.

Furthermore, a bypass channel is formed in the valve housing between thefeed opening and the pilot hole. In a switching valve, a sealing elementarranged on the valve-closing member buts against the valve seat,wherein a closing force from a closing spring acting on the closing bodyis completely transferred to the sealing element for the sealingarrangement.

The object of the invention is to propose a valve arrangement and aswitching valve having such a valve arrangement, which allows for anincreased service life, in particular also when using different media,while maintaining the sealing effect.

The object is achieved by a valve arrangement in which the valve seatcomprises a stop surface and a sealing surface which are oriented so asto be adjacent to one another, and the valve-closing member comprises asupporting surface and a gasket surface arranged so as to be adjacentthereto, wherein an elastic sealing element is provided on the valveseat or valve-closing member, on which sealing element the sealingsurface or gasket surface is formed, and the sealing surface or thegasket surface comprises a sealing projection, which is oriented towardsthe opposite gasket surface or sealing surface, and wherein thesupporting surface of the valve-closing member and the stop surface ofthe valve seat but against one another in a closed position of thevalve-closing member in the valve seat and form a travel limitationbetween the valve-closing member and the valve seat, wherein the sealingprojection is at least partially pressed into the sealing element. Thisvalve arrangement makes it possible for force on the elastic sealingelement to be relieved in the closed position of the valve-closingmember relative to the valve seat, since the supporting surface and thestop surface tightly abut one another in the closed position such thatthe closing force of the valve-closing member does not exert its fulleffect on the seal. At the same time, owing to the design of the sealingprojection, sufficient sealing is provided by a form fit between thesealing projection and the opposite surface, i.e. the sealing surface orthe stop surface. This form-fitting sealing is possible when the sealingprojection is provided on the elastic sealing element and abuts anopposite sealing surface or gasket surface, such that the projectingvolume of the sealing projection is pressed into the sealing element.This form-fitting sealing is also provided when the sealing projectionis provided on the stop surface or supporting surface and is at leastpartially pressed into the elastic sealing element such that a volume inthe circumference of the sealing projection is displaced in the elasticsealing element by the sealing projection, which is rigidly formedopposite the elastic sealing element, on the stop surface or thesupporting surface.

This valve arrangement can preferably be used for an NC (normallyclosed) switching valve and also for an NO (normally open) switchingvalve. In an NC switching valve, the valve-closing member is arranged ina closed position relative to the valve seat in a starting position. Inan NO switching valve, the valve-closing member is raised relative tothe valve seat in a starting position.

It is preferably provided that the valve body comprises a sealing sleeveand a valve body, which valve body is at least partially surrounded bythe sealing sleeve and a sealing element is provided between the sealingsleeve and the valve body. As a result, the sealing element can beretained relative to the valve body in a simple manner. In addition,different geometries of the sealing element can be used in a simplemanner.

In a valve piston, which is preferably constructed from the valve bodyand the sealing sleeve fastened thereto, an end face of the sealingsleeve, can form the supporting surface, which is provided for limitingthe travel of the valve-closing member in the closed position relativeto the valve seat. Alternatively, it may be provided that the supportingsurface is provided on an end face of the valve body pointing towardsthe valve seat.

Advantageously, a receiving volume for the elastic sealing element isformed between the valve body and the sealing sleeve, wherein thesealing element inserted into the receiving volume is smaller in volumethan the receiving space. As a result, the receiving volume is notcompletely filled by the sealing element. This has the advantage that,if the sealing element swells up or if the sealing element increases involume, for example due to temperature and/or pressure, the sealingelement can expand in the receiving volume and the sealing surface orgasket surface remains unaffected.

Advantageously, it is provided that the sealing sleeve, which isarranged on the valve body and surrounds the valve body on the outsideat least in part, comprises a radially inwardly projecting annularcollar on an end face, which collar acts on an outer circumference ofthe sealing element and the sealing element is fixed in axial directionin the receiving space relative to the valve body. The outercircumference of the sealing element comprises preferably radially in aperipheral direction at least an interruption or a depression.Alternatively, the sealing sleeve, which can be inserted into the valvebody, can comprise a radially outwardly projecting annular collar on anend face, which collar acts on an inner circumference of the sealingelement and fixes it in the receiving space relative to the valve body.The first alternative is preferably provided for smaller diameters ofthe through-hole in the valves. The second alternative is preferablyprovided for larger through-holes in the valve, in which larger sealingdiameters are preferably also required. In both cases, it is madepossible for the sealing element to be mounted relative to the valvebody together with the sealing sleeve in a simple manner.

It is advantageously provided that the sealing element is fixedlyretained or movable guided in a direction, preferably in an axialdirection of the valve body, in a form-fitting and/or force-lockedmanner, in particular in a tightly compressed manner, by the annularcollar of the sealing sleeve and a free space remains in the receivingspace in another direction, preferably in a radial direction. As aresult, with regard to the opening and closing movement for the sealingarrangement, defined ratios are provided in the closed position of thevalve-closing member relative to the valve seat, whereas the sealingelement can expand in the radial direction if necessary.

It is advantageously provided that the sealing projection is formed as acircumferential bead, which is provided on the sealing element or on thesealing sleeve or valve-closing member or on the valve seat. A radiallycircumferential bead of this kind is simple to produce in terms ofgeometry and can provide sufficient sealing.

Furthermore, between the sealing element and the valve body there ispreferably at least one sealing lip or at least one sealing ringprojecting in the radial and/or axial direction. This ensures that acirculation of the medium to be controlled between the valve body andthe sealing element is prevented, so that a leakage flow is preventedeven when the sealing element is in contact with the valve closingmember towards the valve seat.

Furthermore, the valve body and the sealing element are preferablyguided in the radial direction by the sealing sleeve and areaccommodated so that they can be displaced relative to one another inthe axial direction. In this arrangement, the sealing element and thevalve body are loosely inserted in the sealing sleeve and are thusdisplaceable relative to one another in the axial direction.

According to an alternative embodiment of the valve piston, the sealingsleeve is pressed onto the valve body, glued onto it or connected toeach other by a snap-in connection. Alternatively, after the sealingsleeve has been placed on the valve body, at least onesubstance-to-substance connection can be provided. Furthermore, thevalve body can be fixed to the valve body by beading an edge of thesealing sleeve. Furthermore, the sealing sleeve can alternatively fixthe valve body within the sealing sleeve by beading its edge, whereby agap is formed between the valve body and the beading or the beaded edgeof the sealing sleeve, so that the valve body is held in the sealingsleeve with axial play.

According to an alternative embodiment of the valve arrangement, thevalve body of the valve piston and the sealing element are produced as atwo-component injection-molded part. This configuration makes itpossible for a valve piston for a valve arrangement to be produced inone process. In this embodiment, additional mounting of a sealing sleeveto fix the sealing element to the valve body can be omitted.Furthermore, alternatively to the embodiment of the valve body and thesealing element in the form of a two-component injection-molded part,the sealing element can be connected to the valve piston by an adhesivebond and/or a press fit. By means of this adhesive bond and/or pressfit, a part of the sealing element can also engage behind a portion ofthe valve piston for improved fixing.

According to a first alternative embodiment of the valve arrangement, itis provided that the sealing projection is arranged on the valve seatand projects in the stroke direction of the valve-closing memberrelative to the stop surface of the valve seat. This sealing projectionon the sealing surface and the stop surface are advantageously made ofone material and are assigned to a through-opening on which the valveseat is formed.

Alternatively, it may be provided that the sealing projection isprovided on the elastic sealing element, which is preferably arranged onthe valve-closing member and points towards a sealing surface on thevalve seat, which surface adjoins the stop surface. In this case, thesealing surface and the stop surface can be in one plane.

It is advantageously provided that the sealing projection preferablyprojects relative to the adjacent stop surface or supporting surface bybetween 0.05 mm and 0.5 mm.

In the advantageous embodiment of the valve arrangement in which thevalve seat comprises the stop surface and, adjacently thereto, thesealing surface comprising the sealing projection and the elasticsealing element is provided on the valve-closing member so as to beopposite the sealing projection, the sealing projection can displace avolume of from 1% to 30% of the sealing element in the sealing elementwhen the valve-closing member is arranged in a closed position relativeto the valve seat. This allows for sufficient sealing or elasticdeformation of the sealing element.

Furthermore, it is preferably provided that the sealing projectionprovided on the sealing surface of the valve seat is provided for athrough-opening having a diameter of from 1 mm to 40 mm.

Another preferred configuration of the valve arrangement provides that apilot valve is provided opposite the valve-closing member of the valvepiston. This pilot valve comprises a pilot hole in the valve body of thevalve piston, which passes through the valve body and opens into thethrough-hole. Furthermore, a travel-generating device is provided, whichhas an actuatable tappet, which receives a closing body that closes thepilot hole and can be transferred into an open position that unblocksthe pilot hole with the closing body. A bypass channel is preferablyformed between the feed opening and the pilot hole. This valvearrangement may thus not only be provided in a switching valve, but alsoin a valve comprising a pilot valve.

It is preferably provided that the sealing sleeve is pressed onto orglued to the valve body or bonded to said valve body at least in partafter positioning the sealing sleeve relative to the valve body. Thisallows for simple mounting of the sealing sleeve relative to the valvebody while integrating the sealing element.

According to a preferred embodiment, it is provided that the sealingsleeve fastened to the valve body comprises a radially outwardlydirected shoulder, on which a return element acts which is guidedbetween the valve seat and the valve piston. This shoulder is inparticular provided when the valve piston is designed as a pilot valve,meaning that an opening movement of the valve piston relative to thevalve seat is limited.

It is preferably provided that the bypass channel is formed by a bypasschannel between an outer circumference of the sealing sleeve arranged onthe valve body and a guide bushing of the tappet by a clearance betweenthe sealing sleeve and the guide bushing, or that a flattened region ora longitudinal groove is formed at least on the outer circumference ofthe sealing sleeve. As a result, it is possible to guide the valvepiston in the guide bushing of the tappet in a structurally simplemanner and, at the same time, for the function of the pilot valve, toform a bypass channel through which the medium can reach the pilot-valvehole.

Another preferred configuration of the valve piston provides that thesealing sleeve and the valve body are pressed together in a region,which is within the radially outwardly projecting shoulder. By means ofthis radially outer circumferential shoulder, an increased force can beachieved in order to act on the valve body in the region, which extendsover the width of the shoulder when viewed in the axial direction. Inanother region, a small annular gap can be formed between the sealingsleeve and the valve body in the axial direction, which extends in theopposite direction to the valve-closing member. It is preferablyprovided that knurling, in particular longitudinal knurling, is providedon the outer circumference of the valve body. This allows for pressingtogether the sealing sleeve and the valve body to be simplified.

Furthermore, it is preferably provided that the valve body comprises apilot valve seat that is oriented towards the pilot hole and is made ofa plastics material, in particular of Teflon, which is preferablypressed into the valve body in the form of a ring. As a result, it isalso possible for the leakage rate to be reduced. In addition, switchingnoise can be minimized.

Furthermore, the object of the invention is achieved by a switchingvalve for regulating a mass flow in a refrigerating circuit or a heatingcircuit, which comprises a valve housing having a feed opening and adischarge opening, and comprises a valve piston, which comprises avalve-closing member, which points towards the discharge opening andbuts in a closing position on a through-hole between the feed-openingand the discharge opening around in a valve seat in a closing position,wherein the switching valve comprises a valve arrangement according toany of the preceding embodiments.

The invention as well as advantageous embodiments and developmentsthereof are described and explained in greater detail in the followingwith reference to the examples shown in the drawings. The features foundin the description and the drawings can be implemented according to theinvention either individually or together in any combination. In thedrawings:

FIG. 1 is a schematic sectional view of a switching valve,

FIG. 2 is a schematically enlarged view of a valve arrangement of theswitching valve according to FIG. 1 in an open position,

FIG. 3 is a schematically enlarged view of the valve arrangementaccording to FIG. 2 in a closing phase,

FIG. 4 is a schematically enlarged view of the valve arrangementaccording to FIG. 2 in a closed position,

FIG. 5 is a schematically enlarged view of a valve piston according toan alternative embodiment to FIGS. 1 to 4,

FIG. 6 is a perspective view of an alternative embodiment of theswitching valve to FIG. 1,

FIG. 7 is a schematic sectional view of the switching valve according toFIG. 6 in a closed position,

FIG. 8 is a schematic sectional view of the switching valve according toFIG. 6 in an open position,

FIG. 9 is a schematically enlarged sectional view of the valvearrangement according to FIG. 7 in the closed position,

FIG. 10 is a schematically enlarged sectional view of the valvearrangement according to FIG. 8 in an open position,

FIG. 11 is a schematically enlarged sectional view of an alternativeembodiment of the valve arrangement to FIG. 9 in a closed position,

FIG. 12 is a schematic sectional view of the valve arrangement accordingto FIG. 11 in an open position,

FIG. 13 is a schematically enlarged sectional view of an alternativeembodiment of the valve arrangement according to FIG. 9 in a closedposition,

FIG. 14 is a schematically enlarged sectional view of the valvearrangement according to FIG. 13 in an open position,

FIG. 15 is a schematically enlarged sectional view of an alternativeembodiment of the valve arrangement to FIG. 13 in a closed position,

FIG. 16 is a schematically enlarged sectional view of the valvearrangement according to FIG. 15 in an open position,

FIG. 17 an alternative embodiment of the valve closing member to FIG. 2,

FIG. 18 a schematic sectional view of an alternative embodiment to FIG.17,

FIG. 19 a schematic sectional view of a further alternative embodimentto FIG. 2, and

FIG. 20 a schematic sectional view of a further alternative embodimentto FIG. 2.

FIG. 1 is a schematic sectional view of a first embodiment of aswitching valve 11 according to the invention. This switching valve 11comprises a valve housing 12 comprising a feed opening 14 for a massflow, in particular a coolant, as well as a discharge opening 15 and achamber 17 that connects the feed opening 14 and the discharge opening15, or a coolant channel. The feed opening 14 and the discharge opening15 each comprise connections for supply lines or other components.

The chamber 17 in the valve housing 12 is open towards a housing side 18to which a travel-generating device 21 is detachably fastened. Thechamber 17 transitions into a through-hole 23, which is surrounded by avalve seat 24, which a valve-closing member 26 of a valve piston 27 bustagainst in a closed position 28.

At its end opposite the valve-closing member 26, the valve piston 27comprises a pilot hole 32, which can be closed by a closing body 33. Thepilot hole 32 and the closing body 33 form a pilot valve 31. Thisclosing body 33 is rigidly arranged on a tappet 35, which can be movedup and down or back and forth by the travel-generating device 21.

According to this embodiment, the travel-generating device 21 comprisesan armature tube 36, to which a core 37 is assigned. A coil 38 surroundsthe armature tube 36, which is in turn integrated in a yoke 39. Thetravel-generating device can be actuated and held by electricalconnection lines 41.

The tappet 35 is mounted so as to be movable relative to the armaturetube 36 while interposing a return spring 43 towards the core 37, i.e.,when energizing the coil 38, the tappet 35 is drawn into the armaturetube 36 counter to the spring force of the return spring 43 and, whenthe coil 38 is switched off, the return spring 43 transfers the tappet35 into a closing movement and arranges the tappet 35 in a closedposition, as shown in FIG. 1. In this case, the closing body 33 engagesin the pilot hole 32 in the valve piston 27. The valve-closing member 26closes the through-hole 23 and buts against the valve seat 24. The valvepiston 27 is preferably guided in a guide bushing 46 that can beinserted into the valve housing 12. Alternatively, the valve piston 27can also be guided directly on a wall portion of the chamber 17 that isopen towards a housing side 18. A bypass channel 48 is provided betweenthis wall portion of the guide bushing 46 or chamber 17 and the valvepiston 27, meaning that a connection is established between the accessopening 14 and the pilot valve 31. After raising the closing body 33 outof the pilot hole 32, the mass flow can flow through the pilot hole 32into the through-hole 23, since the pilot hole 32 extends through thevalve piston 27 in its entirety as far as the valve-closing member 26.Subsequently, the valve piston 27 lifts off from the valve seat 24 withthe assistance of the spring element 67.

The valve 11 shown in FIG. 1 is what is known as an NC valve (normallyclosed valve), i.e., when a coil 38 is not energized, the valve 11 isclosed and a passage between the feed opening 14 and the dischargeopening 15 is blocked. In a valve 11 of this kind, a monostabletravel-generating device 21 is used, for example, which only maintains aposition of the tappet 35 for as long as the coil 38 is energized.

FIG. 2 is a schematically enlarged view of a valve arrangement 51. Thisvalve arrangement 51 is provided in the switching valve 11 according toFIG. 1, for example. The valve arrangement 51 comprises the valve seat24 and the valve-closing member 26. The valve seat 24 comprises asealing surface 52 and a stop surface 53. This sealing surface 52 andthe stop surface 53 are preferably adjacent to one another or transitioninto one another. The sealing surface 52 preferably surrounds thethrough-hole 23. The sealing surface 53 extends outside the stop surface52. A sealing projection 55 is preferably formed on the sealing surface52. For example, this sealing projection 55 is bead-shaped,semi-circular or arc-segment-shaped. This sealing projection 55 projectsin the axial direction towards the valve-closing member 26 opposite thestop surface 53. The sealing surface 52 and the stop surface 53 arepreferably made of the same material, and in particular the sealingsurface 52 and the stop surface 53 are integrally molded directly on thevalve housing 12. Alternatively, it may also be provided that the valveseat 24 is formed as an insertion element, which can be fastened to thevalve housing 12 so as to face towards the through-hole 23.

The valve seat 24 may also consist of and be composed of separateelements, wherein one element comprises the sealing surface 52 andanother element comprises the stop surface 53. Just one of the elements,i.e. the sealing surface 52 or the stop surface 53, can also be designedto be separate and can form the valve seat 24 together with the otherelements that are arranged directly on the valve housing 12.

For example, the through-hole 23 has a diameter of from 1 mm to 40 mm.The sealing projection 55 may project relative to the adjacent stopsurface 53 by 0.05 mm to 0.5 mm.

The valve piston 27 comprises the valve-closing member 26 in thedirection of the valve seat 24. The valve-closing member 26 comprises asupporting surface 62 and a gasket surface 59. They are preferablyadjacent to one another. According to the embodiment, the valve-closingmember 26 is formed by a sealing element 57 and a sealing sleeve 61. Thesealing element 57 is retained so as to be fixed relative to the valvebody 58 of the valve piston 27 by means of the sealing sleeve 61. Thesealing sleeve 61 comprises the supporting surface 62 at the end face.The gasket surface 59 is provided so as to be adjacent thereto. Thisgasket surface 59 is preferably radially within the supporting surface62. The sealing surface 59 is preferably provided on the sealing element57 at the end face so as to point towards the valve seat.

The sealing element 57 is positioned in a receiving space 63 formedbetween the sealing sleeve 61 and the valve body 58. The sealing sleeve61 comprises an annular collar 64, which projects radially inwards, atthe end face. The sealing element 57 is preferably stepped, so as tohave two cross sections of different widths. As a result, the sealingelement 57 can be fixed by the smaller cross section at the end facerelative to the valve body 58 by the annular collar 64. Furthermore, theannular collar 64 fixes the larger cross section of the sealing element57 relative to the valve body 58 in the axial direction. A free space 65is formed in the receiving space 63 between the sealing element 57 andthe sealing sleeve 61, such that the sealing element 57 having thelarger annular cross section can expand radially in this region. Thevalve-closing member 26 preferably comprises, in one plane, the sealingsurface 59 of the sealing element 57 and the supporting surface 62 onthe sealing sleeve 61.

The valve-closing member 26 is shown in an open position relative to thevalve seat 24. The opening movement of the valve-closing member 26 isassisted by the spring element 67, which acts in the direction of thetappet 35.

The maximum open position of the valve-closing member 26 is limited bythe sealing sleeve 61. A radially outwardly pointing shoulder 68 of thesealing sleeve 61 can but against the guide bushing 46. On the oppositeside, the spring element 67 acts on the shoulder 68 and is also guidedin part by an outer face of the annular collar 64.

The bypass channel 48 is formed between an outer circumference of thesealing sleeve 61 and the guide bushing 46. In this case, it may beprovided that longitudinal grooves are provided on the outercircumference of the sealing sleeve 61 and/or that longitudinal groovesare provided in the guide bushing 46. Alternatively, the sealing sleeve61 may comprise one or more flattened regions on the outercircumference. This has the advantage that radial guidance of thesealing sleeve 61 in the guide bushing 46 is retained but sufficientfree space is still provided for the medium to flow from the chamber 17to the pilot hole 32.

The sealing sleeve 61 is preferably pressed onto the valve body 58. Thesealing element 57 is preferably placed onto a sleeve-like portion 69 ofthe valve body 58. The valve body 58 is then inserted into the sleeveportion 70 of the sealing sleeve 61 until the annular surface 71 of thevalve body 58 buts against a complementary annular surface in thesealing sleeve 61. This axially orients the sealing sleeve 61 relativeto the valve body 58. At the same time, a planar end-face configurationof the valve-closing member 26 in the direction of the valve seat 24 canbe provided thereby. In addition, the annular collar 64 can connect thesealing element 57 to the valve body 58 in a force-locked manner in theaxial direction. A press fit is formed between the valve body 58 and thesealing sleeve 61 in a region in which the shoulder 68 is formed. Thesleeve portion 70 that is attached thereto can still be formed with asmall gap from the valve body 58.

The pilot valve 31 is formed on the valve body 58 so as to be oppositethe valve-closing member 26. A pilot-valve seat 73, which is insertedinto, in particular pressed into, the valve body 58, is preferablyprovided. This preferably consists of polytetrafluoroethylene. Thetappet 35 closes the pilot hole 32 in the open position of thevalve-closing member 26.

The energizing of the travel-generating device 21 is switched off inorder to move the valve-closing member 26 from the open position intothe closed position. The return element 43 pushes the tappet 35 and thusthe valve-closing member 26 in the direction of the valve seat 24.

FIG. 3 shows a closing phase of the valve piston 27. In this closingphase, the interruption of the flow passing through the through-hole 23begins. In the closing phase shown, the gasket surface 59 of the sealingelement 57 buts against the sealing surface 52 of the valve-closingmember 24, in particular by means of the sealing projection 55.

FIG. 4 is a schematically enlarged sectional view of the valvearrangement 51 in the closed position of the valve-closing member 26relative to the valve seat 24. The closing movement of the valve piston27 onto the valve seat 24 is limited by the supporting surface 62, whichbuts against the stop surface 53 of the valve seat 24. As a result, adefined form fit is produced with a predetermined force between thegasket surface 62 and the sealing surface 52 of the valve seat 24. Thesealing projection 55 preferably displaces a volume in the sealingelement 57 of from 1% to 30%, for example. This is sufficient for asealing arrangement. At the same time, the sealing element is preventedfrom being squashed or from yielding, or from being permanently damaged.

In the closed position 28 of the valve-closing member 26 relative to thevalve seat 24, a force-locked fit is provided between the stop surface53 of the valve seat 24 and the supporting surface 62 of thevalve-closing member 26 or the sealing sleeve 61. A form fit is formedbetween the sealing surface 52 of the valve seat 24 and the gasketsurface 59 of the sealing element 57.

Alternatively, it may be provided that the sealing projection 55 isformed on the sealing element 57 and the sealing surface 52 of the valveseat 24 is formed as a planar surface, in the same way as the stopsurface 53, and is preferably formed in the same plane.

Furthermore, it may alternatively be provided that the sealing element57 is provided on the valve seat 24, such that the arrangement shown inFIGS. 2 to 4 is reversed.

FIG. 5 is a schematically enlarged sectional view of an alternativeembodiment of the valve-closing member 26 to FIGS. 1 to 4. In theembodiment according to FIGS. 1 to 4, the sealing sleeve 61 surrounds anouter circumference of the valve piston 27 at least in part and fixesthe sealing element 57 relative to the valve piston 27.

In the embodiment according to FIG. 5, the sealing sleeve 61 canlikewise be fastened to the valve piston 27 in a force-locked and/orform-fitting manner. In this case, the sealing sleeve 61 is insertedinto the valve piston 27 in the region of the pilot hole 32. The sealingsleeve 61 comprises an inner through-hole, which forms part of the pilothole 32. A radially outwardly directed annular collar 64 is provided onthe end face of the sealing sleeve 61. The sealing element 57 isretained so as to be fixed relative to the valve piston 27, inparticular relative to the valve body 58, by means of this annularcollar 64. In this case, a free space 65 is preferably formed betweenthe sealing element 57 and the sealing sleeve 61. This may be acircumferential channel or gap. A gasket surface 59 of the sealingelement 57 is recessed relative to the supporting surface 62 of thesealing sleeve 61. As a result, by analogy with the above-describedembodiment of the valve arrangement 51 according to FIGS. 1 to 4, travellimitation of the valve-closing member 26 relative to the valve seat 24is provided.

In this embodiment according to FIG. 5, a bypass channel 48 may beprovided in the form of a flattened region or depression on an outercircumference of the valve body 58. The shoulder 68 is preferablyprovided in one piece on the valve body 58. This shoulder may also beformed by a separate, pressed-on part. Furthermore, a pilot valve seat73 may likewise be fitted to the valve body 58.

Moreover, the above configurations and alternatives according to FIGS. 1to 4 apply to these embodiments according to FIG. 5.

FIG. 6 is a perspective view of a switching valve 11 in the form of anon-return valve. This non-return valve 11 comprises a valve housing 12and a main housing 13. The valve housing 12 is connected to the mainhousing 13 by an interface 16. As a result, the valve housing 14 can bedetached from the main housing 13.

The structure of the switching valve 11 is clear from the sectional viewaccording to FIG. 67. This sectional view shows the switching valve 11in a closed position 28. FIG. 8 is a schematic sectional view of theswitching valve 11 in an open position 29.

The valve housing 12 is advantageously formed in one piece. This valvehousing consists of plastics material, for example, and preferably has acage-like construction. A feed opening 14 is provided on an end face 81of the valve housing 12. One or more discharge openings 15 are providedin a radial circumferential wall of the valve housing 12. Thethrough-hole 23 is arranged therebetween. The valve piston 27 comprisingthe valve-closing member 26 is provided on the valve housing 12. Thevalve seat 24 surrounds the through-hole 23. The valve piston 27comprises at least one rod-shaped guide portion 82, which is guided in ahole portion 83 of the main housing 13. In addition, guide fins 84 canbe provided on the valve piston 27. These guide fins 84 compriseradially outwardly pointing guide portions which act on an inner face ofthe valve housing 12 and guide the valve piston 27 in the radialdirection during an opening and closing movement of the valve piston 27relative to the valve seat 24. A spring element 67, by means of whichthe valve piston 27 is retained in a closed position 28, is providedbetween the valve piston 27 and the main housing 13. In this closedposition 28, the valve-closing member 26 buts against the valve seat 24and closes the through-opening 23. Sealing elements 86, in particularO-ring seals, may be provided on an outer circumference of the mainhousing 13 and/or the valve housing 12. As a result, the switching valve11 can be positioned in a sealing manner in a connection point between afeed opening 14 and a discharge opening 15.

In this switching valve 11, it is for example provided that a medium isfed in the axial direction along the longitudinal axis of the switchingvalve 11 and the medium is discharged in the radial direction via thedischarge openings 15.

FIG. 9 is a schematically enlarged sectional view of the valve-closingmember 26 and the valve seat 24 in a closed position 28. FIG. 10 showsthe valve arrangement 51 according to FIG. 9 in an open position 29.

The structure of the valve arrangement 51 according to FIGS. 9 and 10corresponds to the structure, arrangement and embodiments that aredescribed in FIGS. 2 to 4.

The only difference is that, in the valve seat 24, the stop surface 53is assigned to the through-hole 23 and the sealing surface 52 isprovided radially outside the stop surface 53. Alternatively, a reversalmay also be provided by analogy with the valve arrangement 51 accordingto FIGS. 2 to 4.

FIGS. 11 and 12 show an alternative configuration of the valvearrangement 51 to FIGS. 9 and 10. In this alternative embodiment, it isprovided that the sealing projection 55 is provided on the sealingelement 57. The sealing surface 52 can be formed as a plane as a result.

The embodiments according to FIGS. 9 to 12 also show that the stopsurface 53 can also be oriented towards the sealing surface 52 on thevalve seat 24 such that they are at an obtuse angle to one another. Insuch a switching valve 11 according to FIG. 6, it may also be providedthat the sealing surface 52 and the stop surface 53 of the valve seat 24are in a common plane, in particular a common radial plane. Thesupporting surface 52 and the gasket surface 59 of the valve-closingmember 26 are designed to be complementary to one another.

FIG. 13 is a schematically enlarged sectional view of an alternativeembodiment of the valve-closing member 26 to FIG. 9 in the closedposition 28. FIG. 14 shows the alternative embodiment of thevalve-closing member 26 according to FIG. 13 in an open position 29.

This alternative embodiment of the valve-closing member 26 differs fromthe embodiment according to FIG. 9 in that a sealing sleeve 61 is notprovided. Instead, the valve-closing member 26 consisting of the valvebody 58 and the sealing element 57 is formed as a single component,which is produced as a two-component injection-molded part. The valvebody 58 is formed by the hard component. The soft component is used toproduce and injection-mold the sealing element 57 onto the valve body58. In addition, the comments made with regard to FIGS. 9 and 10 areapplicable.

FIG. 15 shows an alternative embodiment of the valve-closing member 26to FIG. 13 in the closed position 28. FIG. 16 is a schematicallyenlarged view of the valve-closing member 26 according to FIG. 15 in anopen position 29 relative to the valve seat 24. In this embodiment too,the sealing element 57 and the valve body 58 are formed as atwo-component injection-molded part. The embodiment according to FIGS.15 and 16 differs from the embodiment according to FIGS. 13 and 14 inthat the projection 55 is integrally molded on the sealing element 57.In the configurations according to FIGS. 13 and 14, the projection 55 isprovided so as to be adjacent to the stop surface 53 on the valve seat24.

FIG. 17 shows a schematic sectional view of an alternative embodiment ofthe valve closure member 26 to FIG. 2. This valve closure member 26encloses the sealing sleeve 61, in which a valve body 58 is inserted.This valve body 58 rests with a support surface 62 against a radiallyinwardly oriented annular surface 71 in the sealing sleeve 61. At thefront end of the valve body 58, this receives the sealing element 57 atits attachment section 69. A radially inwardly facing annular collar 64of the sealing sleeve 61 abuts a radially outer circumference of thesealing element 57. In this embodiment, the sealing element 57 has aradially outwardly facing annular bead 77 that does not extendcompletely along the height of the sealing element 57. As a result, afree space 65 is formed. This annular bead 77 is not fullycircumferential when viewed in the axial direction, but has one or moreinterruptions 76 (see FIG. 18) or depressions. This allows the medium tobe controlled, which enters the free space 65, to flow out again viathese interruptions 76 or depressions in the annular bead 77.

For fixing the sealing element 57 and the valve body 58 in the sealingsleeve 61, a beading 78 is provided in the present embodiment as analternative to the pressed embodiment in FIG. 2. An upper edge of thesealing sleeve 61 is beaded. This presses the valve body 58 onto thering surface 71 and fixes it in place. At the same time, the sealingelement 57 is held fixed to the annular collar 64, with the annular bead77 supported on the annular collar 64 and held fixed.

FIG. 18 shows an alternative embodiment to FIG. 17. In this embodimentaccording to FIG. 18, a beading 78 is also provided. However, a gap 79is formed between the beading 78 and the valve body 58. This gap 79 canalso be formed by shortening the axial length of the valve body 58compared to the embodiment in FIG. 17.

FIG. 19 shows another alternative embodiment of the valve closure member26 to FIG. 2. In this embodiment, instead of a press connection betweenthe valve body 58 and the sealing sleeve 61, a snap-in connection 91 isprovided. For example, an annular recess is provided on an innercircumference of the sealing sleeve 61, in which a radially outwardlypointing projection on the circumference of the valve body 58 engagesafter contact in the annular surface 71 and fixes the valve body 58 tothe sealing sleeve 61 in a defined position.

FIG. 20 shows another alternative embodiment of the valve closure member26 to the embodiments described above. In this embodiment in FIG. 20,the valve body 58 is axially displaceably positioned in the sealingsleeve 61. The sealing element 57 may also be provided axiallydisplaceable relative to the valve piston 58 and thus also relative tothe sealing sleeve 61. After the valve closure member 26 has beenpositioned between the valve seat and the plunger 35, these components,which are loosely inserted into one another, are captively secured inthe axial direction.

In this embodiment according to FIG. 20, at least one sealing lip 75 ispreferably provided between the sealing element 57 and the valve body 58in the radial and/or axial direction. This at least one sealing lip 75can be provided on the sealing element 57 and/or on the valve body 58.This creates an additional seal between the sealing element 57 and thevalve body 58.

The additional provision of such a sealing lip 75 or a sealing ribaligned with a gap between the sealing element 57 and the valve body 58may also be optionally provided on one of the embodiments describedabove.

1. A valve arrangement for a switching valve for regulating a mass flowin a refrigerating circuit or a heating circuit, comprising a valvehousing, which comprises a feed opening and a discharge opening,comprising a valve piston, which comprises a valve-closing member, whichbuts against a valve seat of a through-hole between the feed opening andthe discharge opening in a closed position and closes the through-hole,the valve seat comprises a stop surface and a sealing surface which areoriented so as to be adjacent to one another, the valve-closing membercomprises a supporting surface and a gasket surface which are orientedso as to be adjacent to one another, an elastic sealing element isprovided on the valve seat or the valve-closing member, on which sealingelement the sealing surface or gasket surface is formed, a sealingprojection is provided on the sealing surface or the gasket surface andis oriented towards the opposite gasket surface or sealing surface, thesupporting surface of the valve-closing member and the stop surface ofthe valve seat but against one another in the closed position and form atravel limitation between the valve-closing member and the valve seat,and the sealing projection is at least partially pressed into thesealing element, wherein the valve piston comprises a sealing sleeve anda valve body, which is at least partially surrounded by the sealingsleeve and the sealing element is housed between the sealing sleeve andthe valve body.
 2. The valve arrangement according to claim 1, whereinthe supporting surface is provided on an end face of the sealing sleeveor on an end face of the valve body facing the valve seat and adjacentto the sealing element.
 3. The valve arrangement according to claim 1,wherein a receiving space is formed between the valve body and thesealing sleeve, and in that the sealing element arranged in thereceiving space occupies a volume, which is smaller than the volume ofthe receiving space.
 4. The valve arrangement according to claim 1,wherein the sealing sleeve that surrounds the valve body on the outsideat least in part comprises a radially inwardly projecting annularcollar, pointing towards the valve seat, which collar acts on an outercircumference of the sealing element and fixes the sealing element inthe receiving space in an axial direction, or in that the sealing sleeveinserted in the valve body comprises a radially outwardly projectingannular collar, pointing towards the valve seat, which collar acts on aninner circumference of the sealing element and fixes it in the receivingspace.
 5. The valve arrangement according to claim 4, wherein the outercircumference or an annular bead of the sealing element comprises in aradially peripheral direction at least one interruption or depression.6. The valve arrangement according to claim 4, wherein the sealingelement is retained in an axial direction relative to the longitudinalaxis of the valve piston, so as to be fixed in a form-fitting orforce-locked manner or movable guided by the annular collar of thesealing sleeve and is guided in a radial direction relative to thelongitudinal axis of the valve piston.
 7. The valve arrangementaccording to claim 5, wherein the sealing element is retained in aradial direction relative to the longitudinal axis of the valve pistonwith the formation of a free space, in the receiving space.
 8. The valvearrangement according to claim 1, wherein at least one sealing lipprojecting at least in radial or axial direction or at least oneprojecting sealing ring is provided between the sealing element and thevalve body.
 9. The valve arrangement according to claim 1, wherein thesealing sleeve is pressed or glued onto the valve body or is at leastpartially substance-to-substance connected after being placed thereon,or in that the sealing sleeve and the valve body are firmly connected tothe valve body by means of a latching connection or by means of abeading of an edge of the sealing sleeve, or are connected to the valvebody with the formation of a gap between the valve body and the beadingof the sealing sleeve.
 10. The valve arrangement according to claim 1,wherein the valve body and the sealing element are guided in the radialdirection through the sealing sleeve and are accommodated in the sealingsleeve so as to be displaceable relative to one another in the axialdirection.
 11. The valve arrangement according to claim 1, wherein whenthe sealing projection is arranged on the valve seat, the sealingprojection projects in the stroke direction of the valve-closing memberrelative to the stop surface of the valve seat, or wherein the sealingprojection is arranged on the sealing element, the sealing projectionprojects in the stroke direction of the valve-closing member relative tothe supporting surface.
 12. The valve arrangement according to claim 11,wherein the sealing projection projects relative to the adjacent stopsurface or the adjacent supporting surface at a height of from 0.05 mmto 0.5 mm.
 13. The valve arrangement according to claim 1, wherein thesealing projection is provided on the sealing surface of the valve seatand displaces a volume of from 1% to 30% of the sealing element towardsthe valve seat in the closed position of the valve-closing member. 14.The valve arrangement according to claim 1, wherein the valve seatcomprises the stop surface and the sealing surface and the sealingprojection is positioned so as to adjoin the through-hole, wherein thethrough-opening has a diameter of from 1 mm to 30 mm.
 15. The valvearrangement according to claim 1, wherein the valve piston comprises apilot valve opposite the valve-closing member, which pilot valvecomprises a pilot hole in the valve piston which opens into thethrough-hole and comprises a travel-generating device, which has anactuatable tappet which receives a closing body that closes the pilothole and is transferable into an open position that unblocks the pilothole with the closing body.
 16. The valve arrangement according to claim1, wherein the value piston and preferably comprises a bypass channelformed between the feed opening and the pilot hole.
 17. The valvearrangement according to claim 1, wherein the sealing sleeve, startingfrom the annular collar, has a radially outwardly projecting shoulderwhich merges into an outer cylindrical sleeve section of the sealingsleeve, and a spring element is guided between the valve seat and atleast the valve piston on the annular collar or the shoulder of thesealing sleeve.
 18. The valve arrangement according to claim 17, whereina bypass channel is formed between an outer circumference of the sealingsleeve and a guide bushing of the tappet by a clearance or at least oneflattened region formed on the outer circumference of the sealing sleeveor at least one longitudinal channel arranged on the outer circumferenceof the sealing sleeve or on the inner circumference of the guidebushing.
 19. A Non-return valve for regulating a mass flow in arefrigerating circuit or a heating circuit, comprising a valve housing,which comprises a feed opening and a discharge opening, comprising avalve piston, which comprises a valve-closing member, which pointstowards the discharge opening, buts against a valve seat arranged on athrough-hole between the feed opening and the discharge opening in aclosed position and is retained in this closed position by a springelement, wherein the valve seat and the valve-closing member are formedaccording to the valve arrangement according to claim 1.